Die casting machine

ABSTRACT

The machine has a mold closing and locking unit including a first hydraulic device operable to move a movable mold support, guided on columns extending between a fixed supporting yoke and another mold support at the injection side, from an open position to a closed position and inversely, and a second hydraulic device operable to produce the mold locking force. The first hydraulic device comprises pistons secured to the movable mold support and arranged symmetrically to the axis of movement thereof, these pistons operating in working cylinders mounted in the supporting yoke. The second hydraulic device comprises a piston secured centrally to the movable mold support and operating in a nonrotatable locking force cylinder. A cam ring embraces the locking force cylinder and is fixed against axial displacement thereon. This cam ring has cams projecting toward the adjacent surface of the fixed supporting yoke and the cam ring is angularly adjustable between a first position, in which these cams can enter into recesses in the adjacent surface of the fixed supporting yoke, and a second position in which the cams bear against the webs separating the recesses in the adjacent surface and the fixed supporting yoke. The cam ring, in the second position, thus bears axially against the adjacent surface of the fixed yoke to transmit the loading of the locking force cylinder to the fixed yoke, whereby a pressure loading of the locking force cylinder produces a locking stroke, of the second hydraulic device, of only a few mm in length.

[latte tea tet [1 1 11] 3,857,440 [451 Dec. 31, 1974 negg [ DIE CASTING MACHINE [75] Inventor: Edwin Ruegg, Netstal, Switzerland [73] Assignee: Maschinenfabrik und Giesserei Netstal AG [22] Filed: Mar. 14, I973 [21] Appl. No.: 341,111

[30] Foreign Application Priority Data Mar. 22, 1972 Switzerland 4236/72 [52] US. Cl..... 164/341, 425/450 R, 425/DIG. 221, 164/344 [51] Int. Cl B22d 33/04 [58] Field of Search 425/450 R, 450 C, 451, 425/DIG. 221, DIG. 223; 164/341, 303, 306, 312, 113

[56] References Cited UNITED STATES PATENTS 3,270,372 9/1966 Hesse 425/450 3,669,593 6/1972 Cyriax 425/450 X 3,669,599 6/1972 Snider et al 425/450 X 3,697,212 10/1972 Herbst 425/450 Primary ExaminerFrancis S. I-Iusar Assistant Examiner-David B. Smith Attorney, Agent, or FirmMcGlew and Tuttle [57] ABSTRACT The machine has a mold closing and locking unit including a first hydraulic device operable to move a movable mold support, guided on columns extending between a fixed supporting yoke and another mold support at the injection side, from an open position to a closed position and inversely, and a second hydraulic device operable to produce the mold locking force. The first hydraulic device comprises pistons secured to the movable mold support and arranged symmetrically to the axis of movement thereof, these pistons operating in working cylinders mounted in the supporting yoke. The second hydraulic device comprises a piston secured centrally to the movable mold support and operating in a non-rotatable locking force cylinder. A cam ring embraces the locking force cylinder and is fixed against axial displacement thereon. This cam ring has cams projecting toward the adjacent surface of the fixed supporting yoke and the cam ring is angularly adjustable between a first position, in which these cams can enter into recesses in the adjacent surface of the fixed supporting yoke, and a second position in which the cams bear against the webs separating the recesses in the adjacent surface and the fixed supporting yoke. The cam ring, in the second position, thus bears axially against the adjacent surface of the fixed yoke to transmit the loading of the locking force cylinder to the fixed yoke, whereby a pressure loading of the locking force cylinder produces a locking stroke, of the second hydraulic device, of only a few mm in length.

9 Claims, 5 Drawing Figures f 23 '2 l 24 7 21 17 1 22 25 12 11 10 1 L 1 7T a j was R H- A t H A a, I 26 1 I2 I 1 *1 t a PATi-INTED 1 I974 3, 8579 440 sum 10F 5 aesvymo SHEET 2 BF 3 PATENTED UEC3 I I974 PATENTED BEES? I974 saw s 0F 5 nu: CASTING MACHINE FIELD AND BACKGROUND OF THE INVENTION This invention relates to a die casting machine, and particularly to a mold closing and locking unit comprising a hydraulic device operable to move a mold support, guided on columns extending between a fixed supporting yoke and another mold support provided on the injection side, from an open position into a closed position and inversely, and a hydraulic device operable to produce the mold locking force.

Fully hydraulic mold closing and locking units, for example, units in which the closing and opening travel of a movable mold support as well as the locking pressure are effected by means of hydraulic devices, are advantageous, particularly in large die casting machines operating with very high locking forces and large numbers of shots per minute. Known machines of this type, however, are not only complicated but frequently are not sufficiently reliable in service either. Difficulties are caused particularly by air bubbles in the pressure fluid, usually oil, and by the after-aspiration of pressure fluid as produced by the product of the piston cross sectional area, in the locking force producing device, and the respective mold stroke. Moreover, pressure fluid consumption and heating up often result in an uneconomical operation.

SUMMARY OF THE INVENTION The invention is directed to the problem of providing a die casting machine of the mentioned type in which these difficulties are avoided and which, for example, for the movement producing the locking force, would require only a minimum stroke of a few mm while assuring an optimum economical service with a minimum of required space.

To this end, a die casting machine embodying the invention is designed so that the hydraulic device effecting the closing and opening travel is provided with pistons which are secured to the movable mold support and arranged symmetrically to the axis of movement thereof. these pistons operating in working cylinders mounted in a fixed supporting yoke. The hydraulic device producing the locking force comprises a piston which is secured centrally to the movable mold support, and operating in a locking force cylinder. The locking force cylinder is non-rotatable, and a force transmitting ring embraces this cylinder and is fixed against axial displacement thereon. This ring is angularly adjustable on the locking force cylinder between a first position, in which it can be moved axially into openings in the adjacent surface of the fixed yoke, into a second position in which the ring, and thus the locking force cylinder also, bear axially adjacent the adjacent surface of the fixed supporting yoke. Thereby, when the locking force piston is loaded with pressure, a locking piston stroke of only a few mm is produced.

In order to turn the force transmitting ring, the hydraulic rotary piston drive advantageously is provided, and the locking force piston is designed as a hollow piston through which an ejector device may operate.

An object of the invention is to provide a die casting machine having an improved mold closing and locking unit. Another object of the invention is to provide such a die casting machine including novel mold locking force producing means requiring only a very short locking stroke of a few mm in length.

A further object of the invention is to provide such a die casting machine which assures optimum economical service with a minimum of required space.

For an understanding of the principles'of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING In the Drawings:

FIG. 1 is a side elevation view showing a part of a die casting machine comprising a fully hydraulic device for effecting the travel motion and the locking pressure;

FIG. 2 is a cross-sectional view taken on the line II-II of FIG. 1;

FIG. 3 is an axial or longitudinal sectional view of the die casting machine part shown in FIG. 1; and

FIGS. 4 and 5 are axial sectional views illustrating details of the die casting machine part shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The fully hydraulic mold closing and locking unit of the die casting machine, as illustrated in the drawings, comprises a supporting yoke 1 having columns 2 mounted thereon and serving as guides for a movable mold support 3. A second mold support 4, at the injection side of the dies casting machine, is secured to the opposite ends of columns 2. Two lateral cylinders 5, each cooperating with a respective piston 5b and a respective piston rod 5a, are also mounted in yoke 1. Piston rods 5a are secured to movable mold support 3 by threaded engagement with nuts 6 bolted to movable mold support 3. Pressure fluid is supplied to the respec tive cylinder volumes on opposite :sides of each piston 5b through inlets 7 and 8, as shown more particularly in FIGS. 4. The hydraulic elements 5, 5a and 5b serve to effect the mold closing and opening travel.

A hollow or tubular piston 9, bolted to movable mold support 3, cooperates with a locking force cylinder I0 provided with a cover 11. A cam ring 12 is rotatably mounted on cylinder cover 11, and restrained against axial movement relative to cylinder 10 and cover 11. Cam ring 12 can be turned by means of a rotary pistoncylinder device 13, which is mounted on cylinder cover 11. Within piston 9, there is mounted a hydraulic ejector device 14 including a stroke limiting element 15 which, for ready adjustment, is accessible from the exterior through supporting yoke 1. Piston 16 of ejector device 14 is formed with an axial bore extending there through.

Hydraulic mold closing device 9, 10, ll, 12 and 13 serves to produce the mold locking pressure. Cylinder 10 is secured against rotation by means of bolts 17. Temporarily, during a change of the cylinder packing, bolts 17 can be secured to movable mold support 3 by means of screws 18, as shown in FIG. 5. In normal service, screws 18 are removed so that cylinder 10 may move within the range of its strokes, and the threaded holes provided in mold support 3 are closed by appropriate stoppers. In order to absorb the tilting movement which appears during operation of the mold closing device, there are provided guide rods 19 reciprocable in supporting yoke 1 and secured to movable mold support 3 by means of screws 20, as best seen in FIG. 5.

Cam ring 12 is formed with cams 21 which cooperate with recesses 22 or with force transmitting webs 23 of supporting yoke 1. In FIG. 3, the facing surfaces of webs 23 and earns 21 are designated, respectively, 24 and 25.

When the mold is open, cam ring 12 occupies an angular position in which the axial planes of cams 21 and of recesses 22 of supporting yoke l coincide. As pressure fluid is supplied through inlets 8 into lateral cylinders 5, piston rods a move mold support 3 over the travel distance H (FIG. 1) into the closing position of the mold. During this time, the mold locking device is relieved through pressure fluid inlet 26. Once the closing position of the mold is attained, front surfaces 25 of cams 21 are positioned at a small distance of, for example, 3 mm., from the front surfaces 24 of webs 23. As soon as the distance between the surfaces 24 and 25 is sufficient, but not later than arrival of the movable mold into the mold closing position, pressure fluid is supplied into rotary piston-cylinder l3 and cam ring 12 is angularly adjusted so that cams 21 move out of alignment with recesses 22 and into alignment with webs 23. After this position of the parts is attained, pressure fluid is supplied into cylinder volume S through inlet 27 (FIG. 3) whereby the mold locking force is produced through the medium of tubular hollow piston 9. At the same time, pressure fluid in the cylinder volume R is vented through inlet 26.

To open the mold, initially the pressure in cylinder volume S and in lateral cylinders 5 is relieved, through the respective inlets 27 and 8. Thereafter, pressure fluid is supplied to inlet 26 and to cylinder volume R of the mold locking device until the mentioned distance of, for example, 3 mm., between the facing surfaces 24 and 25 of the respective parts 23 and 21 is obtained again. Rotary piston cylinder 13 is then supplied with pressure fluid, to angularly adjust ring 12 so that cams 21 are aligned with recesses 22 of supporting yoke 1. After this angular adjustment of cam ring 12, pressure fluid is supplied into lateral cylinders 5 through inlet 7, the fluid in the volume on the other side of the respective pistons 5b being vented through inlets 8, so that the mold opens. The described cycle of operations may then be re-started.

The hydraulic mold closing and locking unit of the invention has a compact construction and its individual parts are easily accessible. In order to effect the closing and opening travel, on the one hand, and to produce the locking pressure, on the other hand, the unit of the present invention utilizes simple hydraulic mechanisms, with the particular advantage that the mechanism provided for producing the locking force operates with a stroke of only a few millimeters.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. In a die casting machine having a mold closing and locking unit including a first hydraulic device operable to move a movable mold support, guided on columns extending between a supporting yoke and another mold support at the injection side, from an open position to a closed position and inversely, and a second hydraulic device operable to produce the mold locking force, with the first hydraulic device including pistons secured to the movable mold support and arranged symmetrically to the axis of movement thereof, and operating in working cylinders mounted in the supporting yoke, the improvement comprising, in combination, said second hydraulic device comprising a piston secured centrally to said movable mold support and operating in a nonrotatable locking force cylinder; four guide rods reciprocable in said supporting yoke and secured to said movable mold support to absorb the tilting moment produced by said second hydraulic device; a force transmitting ring embracing said locking force cylinder and fixed against axial displacement thereon; said ring being angularly adjustable on said locking force cylinder between a first position, in which it can be moved axially into openings in the adjacent surface of said yoke, and a second position, in which it bears axially against said adjacent surface to transmit the loading of said locking force cylinder to said adjacent surface of said supporting yoke; whereby a pressure loading of said locking force cylinder produces a locking stroke, of said second hydraulic device, of only a few millimeters in length, said piston of said second hydraulic device being a tubular piston; and a hydraulic ejector device concentrically disposed within and axially reciprocable through said tubular piston.

2. In a die casting machine, the improvement claimed in claim 1, in which force transmitting ring is a cam ring having angularly spaced cams arranged to engage, in said first position, in corresponding angularly spaced recesses in said supporting yoke and, in said second position, to engage webs separating said recesses.

3. In a die casting machine, the improvement claimed in claim 2, in which in advance of starting the mold locking, the facing surfaces of said webs and of said cams are spaced apart a few millimeters.

4. In a die casting machine, the improvement claimed in claim 2, in which said locking force cylinder includes a closure at its end adjacent said yoke; said cam ring being mounted on said closure.

5. In a die casting machine, the improvement claimed in claim 4, including bolts on said locking force cylinder extending into bores in said movable mold support to restrain said locking force cylinder against rotation.

6. In a die casting machine, the improvement claimed in claim 5, including screws insertable through said bores to threadedly engage said bolts to secure said bolts to said movable mold support during an exchange of packing of said locking force cylinder; and stoppers engageable in said bores to close the outer ends of said bores upon removal of said screws.

7. In a die casting machine, the improvement claimed in claim 1, including a hydraulic rotary piston-cylinder mounted on that portion of said second hydraulic device remote from said mold, and operable to angularly adjust said force transmitting ring.

8. In a die casting machine, the improvement claimed in claim 1 including a further piston incorporated in said hydraulic ejector device; and mold closing stroke limiting means operatively associated with said further piston.

9. In a die casting machine, the improvement claimed in claim 8, in which said further piston has a bore extending axially therethrough and is accessible both through said movable mold support and said supporting yoke. 

1. In a die casting machine having a mold closing and locking unit including a first hydraulic device operable to move a movable mold support, guided on columns extending between a supporting yoke and another mold support at the injection side, from an open position to a closed position and inversely, and a second hydraulic device operable to produce the mold locking force, with the first hydraulic device including pistons secured to the movable mold support and arranged symmetrically to the axis of movement thereof, and operating in working cylinders mounted in the supporting yoke, the improvement comprising, in combination, said second hydraulic device comprising a piston secured centrally to said movable mold support and operating in a non-rotatable locking force cylinder; four guide rods reciprocable in said supporting yoke and secured to said movable mold support to absorb the tilting moment produced by said second hydraulic device; a force transmitting ring embracing said locking force cylinder and fixed against axial displacement thereon; said ring being angularly adjustable on said locking force cylinder between a first position, in which it can be moved axially into openings in the adjacent surface of said yoke, and a second position, in which it bears axially against said adjacent surface to transmit the loading of said locking force cylinder to said adjacent surface of said supporting yoke; whereby a pressure loading of said locking force cylinder produces a locking stroke, of said second hydraulic device, of only a few millimeters in length, said piston of said second hydraulic device being a tubular piston; and a hydraulic ejector device concentrically disposed within and axially reciprocable through said tubular piston.
 2. In a die casting machine, the improvement claimed in claim 1, in which force transmitting ring is a cam ring having angularly spaced cams arranged to engage, in said first position, in corresponding angularly spaced recesses in said supporting yoke and, in said second position, to engage webs separating said recesses.
 3. In a die casting machine, the improvement claimed in claim 2, in which in advance of starting the mold locking, the facing surfaces of said webs and of said cams are spaced apart a few millimeters.
 4. In a die casting machine, the improvement claimed in claim 2, in which said locking force cylinder includes a closure at its end adjacent said yoke; said cam ring being mounted on said closure.
 5. In a die casting machine, the improvement claimed in claim 4, including bolts on said locking force cylinder extending into bores in said movable mold support to restrain said locking force cylinder against rotation.
 6. In a die casting machine, the improvement claimed in claim 5, including screws insertable through said bores to threadedly engage said bolts to secure said bolts to said movable mold support during an exchange of packing of said locking force cylinder; and stoppers engageable in said bores to close the outer ends of said bores upon removal of said screws.
 7. In a die casting machine, the improvement claimed in claim 1, including a hydraulic rotary piston-cylinder mounted on that portion of said second hydraulic device remote from said mold, and operable to angularly adjust said force transmitting ring.
 8. In a die casting machine, the improvement claimed in claim 1 including a further piston incorporated in said hydraulic ejector device; and mold closing stroke limiting means operatively associated with said further piston.
 9. In a die casting machine, the improvement claimed in claim 8, in which said further piston has a bore extending axially therethrough and is accessible both through said movable mold support and said supporting yoke. 